allow passing a callable to de/serialization funcs (quantumlib#6855)

* allow passing func to de/serialization funcs

* coverage

* simplify

* typecheck

* nit

* mypy

* comments

* comments

Author: senecameeks

cirq-google/cirq_google/api/v2/sweeps.py

@@ -12,12 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Any, cast, Dict, List, Optional
+from typing import Any, cast, Callable, Dict, List, Optional
 
 import sympy
 import tunits
 
 import cirq
+from cirq.study import sweeps
 from cirq_google.api.v2 import run_context_pb2
 from cirq_google.study.device_parameter import DeviceParameter
 
@@ -55,14 +56,18 @@ def _recover_sweep_const(const_pb: run_context_pb2.ConstValue) -> Any:
 
 
 def sweep_to_proto(
-    sweep: cirq.Sweep, *, out: Optional[run_context_pb2.Sweep] = None
+    sweep: cirq.Sweep,
+    *,
+    out: Optional[run_context_pb2.Sweep] = None,
+    sweep_transformer: Callable[[sweeps.SingleSweep], sweeps.SingleSweep] = lambda x: x,
 ) -> run_context_pb2.Sweep:
     """Converts a Sweep to v2 protobuf message.
 
     Args:
         sweep: The sweep to convert.
         out: Optional message to be populated. If not given, a new message will
             be created.
+        sweep_transformer: A function called on Linspace, Points.
 
     Returns:
         Populated sweep protobuf message.
@@ -91,6 +96,7 @@ def sweep_to_proto(
         for s in sweep.sweeps:
             sweep_to_proto(s, out=out.sweep_function.sweeps.add())
     elif isinstance(sweep, cirq.Linspace) and not isinstance(sweep.key, sympy.Expr):
+        sweep = cast(cirq.Linspace, sweep_transformer(sweep))
         out.single_sweep.parameter_key = sweep.key
         if isinstance(sweep.start, tunits.Value):
             unit = sweep.start.unit
@@ -110,6 +116,7 @@ def sweep_to_proto(
         if sweep.metadata and getattr(sweep.metadata, 'units', None):
             out.single_sweep.parameter.units = sweep.metadata.units
     elif isinstance(sweep, cirq.Points) and not isinstance(sweep.key, sympy.Expr):
+        sweep = cast(cirq.Points, sweep_transformer(sweep))
         out.single_sweep.parameter_key = sweep.key
         if len(sweep.points) == 1:
             out.single_sweep.const_value.MergeFrom(_build_sweep_const(sweep.points[0]))
@@ -142,8 +149,17 @@ def sweep_to_proto(
     return out
 
 
-def sweep_from_proto(msg: run_context_pb2.Sweep) -> cirq.Sweep:
-    """Creates a Sweep from a v2 protobuf message."""
+def sweep_from_proto(
+    msg: run_context_pb2.Sweep,
+    sweep_transformer: Callable[[sweeps.SingleSweep], sweeps.SingleSweep] = lambda x: x,
+) -> cirq.Sweep:
+    """Creates a Sweep from a v2 protobuf message.
+
+    Args:
+        msg: Serialized sweep message.
+        sweep_transformer: A function called on Linspace, Point, and ConstValue.
+
+    """
     which = msg.WhichOneof('sweep')
     if which is None:
         return cirq.UnitSweep
@@ -178,31 +194,38 @@ def sweep_from_proto(msg: run_context_pb2.Sweep) -> cirq.Sweep:
             )
         else:
             metadata = None
+
         if msg.single_sweep.WhichOneof('sweep') == 'linspace':
             unit: float | tunits.Value = 1.0
             if msg.single_sweep.linspace.HasField('unit'):
                 unit = tunits.Value.from_proto(msg.single_sweep.linspace.unit)
-            return cirq.Linspace(
-                key=key,
-                start=msg.single_sweep.linspace.first_point * unit,  # type: ignore[arg-type]
-                stop=msg.single_sweep.linspace.last_point * unit,  # type: ignore[arg-type]
-                length=msg.single_sweep.linspace.num_points,
-                metadata=metadata,
+            return sweep_transformer(
+                cirq.Linspace(
+                    key=key,
+                    start=msg.single_sweep.linspace.first_point * unit,  # type: ignore[arg-type]
+                    stop=msg.single_sweep.linspace.last_point * unit,  # type: ignore[arg-type]
+                    length=msg.single_sweep.linspace.num_points,
+                    metadata=metadata,
+                )
             )
         if msg.single_sweep.WhichOneof('sweep') == 'points':
             unit = 1.0
             if msg.single_sweep.points.HasField('unit'):
                 unit = tunits.Value.from_proto(msg.single_sweep.points.unit)
-            return cirq.Points(
-                key=key,
-                points=[p * unit for p in msg.single_sweep.points.points],
-                metadata=metadata,
+            return sweep_transformer(
+                cirq.Points(
+                    key=key,
+                    points=[p * unit for p in msg.single_sweep.points.points],
+                    metadata=metadata,
+                )
             )
         if msg.single_sweep.WhichOneof('sweep') == 'const_value':
-            return cirq.Points(
-                key=key,
-                points=[_recover_sweep_const(msg.single_sweep.const_value)],
-                metadata=metadata,
+            return sweep_transformer(
+                cirq.Points(
+                    key=key,
+                    points=[_recover_sweep_const(msg.single_sweep.const_value)],
+                    metadata=metadata,
+                )
             )
 
         raise ValueError(f'single sweep type not set: {msg}')

cirq-google/cirq_google/api/v2/sweeps_test.py

@@ -153,6 +153,58 @@ def test_sweep_to_proto_points():
     assert list(proto.single_sweep.points.points) == [-1, 0, 1, 1.5]
 
 
+def test_sweep_to_proto_with_simple_func_succeeds():
+    def func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            sweep.points = [point + 3 for point in sweep.points]
+
+        return sweep
+
+    sweep = cirq.Points('foo', [1, 2, 3])
+    proto = v2.sweep_to_proto(sweep, sweep_transformer=func)
+
+    assert list(proto.single_sweep.points.points) == [4.0, 5.0, 6.0]
+
+
+def test_sweep_to_proto_with_func_linspace():
+    def func(sweep: sweeps.SingleSweep):
+        return cirq.Linspace('foo', 3 * tunits.ns, 6 * tunits.ns, 3)  # type: ignore[arg-type]
+
+    sweep = cirq.Linspace('foo', start=1, stop=3, length=3)
+    proto = v2.sweep_to_proto(sweep, sweep_transformer=func)
+
+    assert proto.single_sweep.linspace.first_point == 3.0
+    assert proto.single_sweep.linspace.last_point == 6.0
+    assert tunits.Value.from_proto(proto.single_sweep.linspace.unit) == tunits.ns
+
+
+def test_sweep_to_proto_with_func_const_value():
+    def func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            sweep.points = [point + 3 for point in sweep.points]
+
+        return sweep
+
+    sweep = cirq.Points('foo', points=[1])
+    proto = v2.sweep_to_proto(sweep, sweep_transformer=func)
+
+    assert proto.single_sweep.const_value.int_value == 4
+
+
+@pytest.mark.parametrize('sweep', [(cirq.Points('foo', [1, 2, 3])), (cirq.Points('foo', [1]))])
+def test_sweep_to_proto_with_func_round_trip(sweep):
+    def add_tunit_func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            sweep.points = [point * tunits.ns for point in sweep.points]  # type: ignore[misc]
+
+        return sweep
+
+    proto = v2.sweep_to_proto(sweep, sweep_transformer=add_tunit_func)
+    recovered = v2.sweep_from_proto(proto)
+
+    assert list(recovered.points)[0] == 1 * tunits.ns
+
+
 def test_sweep_to_proto_unit():
     proto = v2.sweep_to_proto(cirq.UnitSweep)
     assert isinstance(proto, v2.run_context_pb2.Sweep)
@@ -188,6 +240,41 @@ def test_sweep_from_proto_single_sweep_type_not_set():
         v2.sweep_from_proto(proto)
 
 
+@pytest.mark.parametrize('sweep', [cirq.Points('foo', [1, 2, 3]), cirq.Points('foo', [1])])
+def test_sweep_from_proto_with_func_succeeds(sweep):
+    def add_tunit_func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            sweep.points = [point * tunits.ns for point in sweep.points]  # type: ignore[misc]
+
+        return sweep
+
+    msg = v2.sweep_to_proto(sweep)
+    sweep = v2.sweep_from_proto(msg, sweep_transformer=add_tunit_func)
+
+    assert list(sweep.points)[0] == [1.0 * tunits.ns]
+
+
+@pytest.mark.parametrize('sweep', [cirq.Points('foo', [1, 2, 3]), cirq.Points('foo', [1])])
+def test_sweep_from_proto_with_func_round_trip(sweep):
+    def add_tunit_func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            sweep.points = [point * tunits.ns for point in sweep.points]  # type: ignore[misc]
+
+        return sweep
+
+    def strip_tunit_func(sweep: sweeps.SingleSweep):
+        if isinstance(sweep, cirq.Points):
+            if isinstance(sweep.points[0], tunits.Value):
+                sweep.points = [point[point.unit] for point in sweep.points]
+
+        return sweep
+
+    msg = v2.sweep_to_proto(sweep, sweep_transformer=add_tunit_func)
+    sweep = v2.sweep_from_proto(msg, sweep_transformer=strip_tunit_func)
+
+    assert list(sweep.points)[0] == 1.0
+
+
 def test_sweep_with_list_sweep():
     ls = cirq.study.to_sweep([{'a': 1, 'b': 2}, {'a': 3, 'b': 4}])
     proto = v2.sweep_to_proto(ls)